Return error when attempting to serialize an empty path (#279)

* Test for empty path warning * Return ErrorCode::EmptyPath when path has too few points
heitzmann · Nov 25, 2024 · 21bbdad · 21bbdad
1 parent 1b36890
commit 21bbdad
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Showing 4 changed files with 39 additions and 3 deletions.
diff --git a/include/gdstk/utils.hpp b/include/gdstk/utils.hpp
@@ -69,6 +69,7 @@ enum struct ErrorCode {
     NoError = 0,
     // Warnings
     BooleanError,
+    EmptyPath,
     IntersectionNotFound,
     MissingReference,
     UnsupportedRecord,

diff --git a/python/gdstk_module.cpp b/python/gdstk_module.cpp
@@ -51,6 +51,9 @@ static int return_error(ErrorCode error_code) {
         case ErrorCode::NoError:
             return 0;
         // Warnings
+        case ErrorCode::EmptyPath:
+            if (PyErr_WarnEx(PyExc_RuntimeWarning, "Empty path.", 1) != 0) return -1;
+            return 0;
         case ErrorCode::MissingReference:
             if (PyErr_WarnEx(PyExc_RuntimeWarning, "Missing reference.", 1) != 0) return -1;
             return 0;

diff --git a/src/flexpath.cpp b/src/flexpath.cpp
@@ -239,7 +239,7 @@ void FlexPath::remove_overlapping_points() {
 
 ErrorCode FlexPath::to_polygons(bool filter, Tag tag, Array<Polygon*>& result) {
     remove_overlapping_points();
-    if (spine.point_array.count < 2) return ErrorCode::NoError;
+    if (spine.point_array.count < 2) return ErrorCode::EmptyPath;
 
     const Array<Vec2> spine_points = spine.point_array;
     uint64_t curve_size_guess = spine_points.count * 2 + 4;
@@ -774,7 +774,7 @@ ErrorCode FlexPath::to_gds(FILE* out, double scaling) {
 
     remove_overlapping_points();
 
-    if (spine.point_array.count < 2) return error_code;
+    if (spine.point_array.count < 2) return ErrorCode::EmptyPath;
 
     uint16_t buffer_end[] = {4, 0x1100};
     big_endian_swap16(buffer_end, COUNT(buffer_end));
@@ -918,7 +918,7 @@ ErrorCode FlexPath::to_oas(OasisStream& out, OasisState& state) {
 
     remove_overlapping_points();
 
-    if (spine.point_array.count < 2) return error_code;
+    if (spine.point_array.count < 2) return ErrorCode::EmptyPath;
 
     bool has_repetition = repetition.get_count() > 1;
 

diff --git a/tests/library_test.py b/tests/library_test.py
@@ -561,3 +561,35 @@ def test_write_min_length_path(
         source.cells[0].paths[0].spine(),
         rw.cells[0].paths[0].spine(),
     )
+
+
+@pytest.mark.parametrize(
+    "simple_path", (True, False),
+)
+@pytest.mark.parametrize(
+    "write_f",
+    (gdstk.Library.write_oas, gdstk.Library.write_gds),
+)
+def test_empty_path_warning(
+    simple_path: bool,
+    write_f: Callable[[gdstk.Library, Union[str, pathlib.Path]], None],
+    tmp_path: pathlib.Path
+):
+    lib = gdstk.Library("test")
+    tol = lib.precision / lib.unit
+
+    # Simple paths are written to GDS & OASIS with PATH records; non-simple
+    # paths are serialized as polygons.
+    path = gdstk.FlexPath(
+        ((0, 0), (tol / 2, 0)),
+        width=0.01,
+        tolerance=tol,
+        simple_path=simple_path
+    )
+
+    cell = gdstk.Cell("top")
+    cell.add(path)
+    lib.add(cell)
+
+    with pytest.warns(RuntimeWarning, match="Empty path"):
+        write_f(lib, tmp_path / "out")